Improving a swimmer's performance, propulsion speed, is a complex process dependent on the science of physics and fluid dynamics and changes to the swimmer's stroke on the order of two or three centimeters. Translation of the science of swimming to effective, practical guidance for solving the problem of improving a swimmer's performance at the Olympic or world record holder level is substantially non-existent. There are no standards that identify the optimum ranges for parameters that define the complex motions of elite swimmers. Even identifying deficiencies in a particular swimmer's mechanics at the centimeter scale is difficult. Providing guidance that enables a swimmer to make the correct mechanical change at this scale has proved elusive. Historically, coaches have provided vague, abstract verbal cues to direct a swimmer to change her stroke. Unfortunately, the swimmer often is unable to translate those cues into mechanical movements that improve performance. For these and other reasons there is a need for the subject matter of the present disclosure.